The most important of Wittgenstein
's works, and almost certainly the most important philosophical
work of the twentieth century. It was published in 1953, two years after his death, but was collected from his working notes for many years before. It represents the greatest achievement of the analytic
approaches to philosophy
; and is a repudiation of all atomistic
doctrines, especially including his own earlier work, the Tractatus Logico-Philosophicus
With the Tractatus in 1921 he thought he had essentially solved the problems of philosophy, and he retired to school-teaching and the odd bit of architecture. He had put forth a pictorial theory of meaning: that the logical structure of language mirrored that of the world. It was immensely influential. But from 1929 Wittgenstein was nagged by doubts, and began to revise his views. He returned to university teaching and developed his new philosophy. He published nothing, but his views began to circulate in typescript, forming what are known as the Blue Book and the Brown Book.
He himself organized his notes, preparing them as if for publication, until 1945. This constitutes the first part of Philosophical Investigations, written out as 693 numbered remarks, following various trails, asking questions, posing hypotheticals, considering unusual situations that threw light on how we behave, speak, and think. Then his notes from 1946 to 1949, forming half as much again, are less organized. On his death in 1951 G.E.M. Anscombe and Rush Rhees prepared it all for publication. The German title is Philosophische Untersuchungen.
Bibliographical details out of the way, I am at a loss for how to begin to convey the philosophical import of the Investigations. It has no essence, no one topic or purpose; but there is a family resemblance among the issues he tackles. I suppose one recurring central question is, What do we do?. When we utter a sentence, when we "mean" something, when we follow a procedure, when we understand a rule, when we have doubts or feel pain or realize or guess or discover or explain, what in fact happens? How do we know we have done it (if we know it)? How would someone else know? Why do we describe it that way, and how can we recognize that someone else is thinking, behaving, feeling, doing as we do?
Unlike in the Tractatus, language is not a description. We don't observe a situation and describe it. Language is something we do: it is a form of life. And there are many different ways we use language. They have no single underlying essence, but have at most a family resemblance, the way games do: not all games are for teams, not all score points, not all are on boards or fields, yet we group things together as games. So our uses of language are varied in their connexions: Wittgenstein in fact calls them language games.
Examples: telling stories, taking orders, asking for directions, trying to work something out, trying to bring something back into mind, expecting an event to happen, teaching, wondering whether something is true, playing a game by rules; and endless others. No one of these can be forced into the same mould as any other, yet they are related in intricate ways.
Early on Wittgenstein writes, "Explanations come to an end somewhere". You don't keep referring language back to more language, more explanation. What actually happens, at some point, is that we do something. We don't analyse how we do it; we don't need a rule to tell us how to follow a rule. What happens is this: we follow the rule.
I was going to bring more details in here but there's so much I could pick out, and I think this is enough for one outline node on the book. I could be here all night cherry-picking quotes.